Linkage arrangement for a wheel loader

Abstract

In the operation of a wheel loader the linkage arrangement that mounts the bucket to the machine often utilizes multiple lift arms and tilting components to accommodate the loading encountered in the various excavation operations. In many instances this hampers visibility to the bucket and also greatly increases the overall weight of the linkage arrangement. The present invention provides a linkage arrangement that utilizes a single boom-type lift arm and a tilting arrangement that is substantially centered along a vertical plane in which the linkage arrangement is moved. In addition, the individual components of the linkage are specifically contoured to provide a sufficient amount of mass in critical areas of loading and reduced areas of mass in non-critical areas. The result is a linkage arrangement that provides excellent visibility to the bucket with greatly reduced overall weight.

I claim: 
     
       1. A linkage arrangement for mounting a bucket to a wheel loader for movement in a generally vertical plane, comprising: a lift arm having a first bifurcated end portion pivotally mountable to the wheel loader at spaced locations and a second bifurcated end portion pivotally mountable to a pair of mounting plates defined by the bucket at spaced locations;   a tilt lever having a first bifurcated end portion pivotally mountable to the mounting plates defined by the bucket at spaced locations that are laterally adjacent and positioned elevationally above the connections between the second end portion of the lift arm and the bucket and a second end portion;   a singular tilt link having a generally uniform configuration, said tilt link having a first end portion pivotally mounted to an upper surface of the lift arm and a second end portion pivotally mounted to the tilt lever at a point that is substantially intermediate the end portions of the tilt lever; and   a tilt cylinder having a first end portion mountable to the wheel loader and a second end portion mounted to the second end portion of the tilt lever.   
     
     
       2. The linkage arrangement as set forth in claim 1 wherein the bucket is moveable in the vertical plane by a pair of lift cylinders connectable to the wheel loader and connected to opposite sides of the lift arm. 
     
     
       3. The linkage arrangement as set forth in claim 2 wherein each lift cylinder has a first end portion connectable to the wheel loader and a second end portion that is pivotally connected to one of a pair of projections that extend from opposing side surfaces defined by the lift arm at a point that is substantially intermediate the first and second end portions of the lift arm. 
     
     
       4. The linkage arrangement as set forth in claim 1 wherein the first end of the tilt link is mounted between a pair of upstanding flanges that extend from an upper surface defined by the lift arm. 
     
     
       5. The linkage arrangement as set forth in claim 1 wherein the second end portion of the tilt lever is bifurcated to form a pair of flanges that are spaced from one another a distance sufficient to receive the second end portion of the tilt cylinder. 
     
     
       6. The linkage arrangement as set forth in claim 1 wherein the lift arm, the tilt lever, the tilt link and the tilt cylinder are all substantially centered along the vertical plane. 
     
     
       7. The linkage arrangement as set forth in claim 1 wherein the lift arm is a one piece casting. 
     
     
       8. The linkage arrangement as set forth in claim 1 wherein the first and second end portions of the lift arm are connected by a connecting portion that has a width that is less than that of the first end portion. 
     
     
       9. The linkage arrangement as set forth in claim 1 further comprising a pair of first mounting plates attachable to a rear portion of the bucket at laterally spaced locations on opposite sides of the vertical plane, each said mounting plate extending in a generally vertical direction and having a lower end portion connected to one of the bifurcations of the lift arm and an upper portion connected to one of the bifurcations of the tilt lever. 
     
     
       10. The linkage arrangement as set forth in claim 9 wherein a second mounting plate is spaced from the lower portions of each of the first mounting plates in an outward direction with respect to the vertical plane, said spacing between the first and second mounting plates being sufficient to receive one of the respective bifurcations defined by the lift arm for pivotal connection to the first and second mounting plates. 
     
     
       11. The linkage arrangement as set forth in claim 10 wherein a third mounting plate is spaced from the upper portions of each of the first mounting plates in a direction towards the vertical plane, said spacing between the first and third mounting plates being sufficient to receive one of the respective bifurcations defined by the tilt lever for pivotal connection to the first and third mounting plates.